Side lead trimmer for electric lamp manufacture



June 28, 1955 v c. E. BECHARD ET AL 2,711,791-

SIDE LEAD TRIMMER FOR ELECTRIC LAMP MANUFACTURE Original Filed Dec. 26, 1951 'Invento'rs Conrad Ebechard Waldemar P. Schoenoff Tir Attorney United States Patent SIDE LEAD TRHVIIVIER FOR ELECTRIC LAMP MANUFACTURE Conrad E. Bechard, Mayfield Heights, and Waldemar P. Schoenofi, Euclid, Ohio, assiguors to General Electric Company, a corporation of New York Original application December 26, 1951, Serial No. 263,458. Divided and this application December 22, 1953, Serial No. 399,7 83

1 Claim. (Cl. 164 -38) This invention relates generally to'electric lamps and their manufacture and more particularly to the operation commonly known as basing, wherein a metal base is fastended to the neck of the bulb, the lead-in wires are connected to the appropriate parts of the base, and the projecting portions of lead-in wires are removed.

The present application is a division of our copending application Serial No. 263,458, filed December 26, 1951, entitled Electric Lamp and assigned to the same assignee as the present invention.

In the commercial production of incandescent lamps, basing is generally made with a finishing machine which comprises a turret or reel having a number of holders mounted on its periphery and in which the bulbs are supported with their bases properly seated on them. Means are provided for intermittently rotating the reel in order to index the bulbs into successive work stations where the various operations are performed automatically for completing the manufacture. The common practice is for the operator to apply the base to the bulb neck and to thread the lead wires, one through the eyelet hole in the end contact of the base, and the other along the side of the bulb neck, previous to inserting the lamp into a holder of the finishing machine. In general, the prior art manufacturing operations included heating the base by suitable means such as gas flames in order to set the basing cement, cutting off the projecting portions of the lead wires, and connecting the lead wires to thebase shell and to the eyelet. The lead-in wires were generally connected by soldering.

More recently it has been proposed to eliminate the solder connection of the side lead-in wire and to substitute in its stead a mechanical connection. It will be appreciated that a solder connection requires the use of a readily soldered metal such as brass for the shell of the base, and that a mechanical connection has the decided advantage of permitting the substitution of less expensive materials such as aluminum. The invention is more particularly concerned with the basing of lamps wherein the side leadin wire of the lamp is wedged between the seal shoulder or neck of the bulb and the shell of its base in order to effect a mechanical contact. sirable that the side lead-in wire be cut off very short. A projecting length of relatively stiff wire is unsightly and also hazardous from the point of view of scratching of the hands in handling. Moreover, the public has become accustomed to incandescent lamps having a soldered side connection, and now tends to regard a lamp having a short length of lead wire projecting from the edge of the base and not soldered, as defective. That tendency is not present when the lead-in wire is cut off right at the edge of the base so that no part thereof appears on casual inspection.

An object of the invention is to provide an improved method of cutting ofi the side lead-in wire in the manufacture of the solderless side contact type of electric lamps, and also to provide a simple and efiective apparatus for the commercial utilization of the method.

In accordance with the invention, the side lead-in wire With such lamps, it is highly de- Patented June 28, 1955 is first wedged between the seal of the bulb and the shell of the base so that any subsequent pulling on the protruding portion of the wire will not exert excessive tension on the lead-in wire where it is hermetically sealed into the bulb. Thereafter the protruding portion of the wire is sheared off against the edge of the base shell by pulling the wire back in a manner to effect a sharp bend in it at the edge of the shell. Where the lead-in wire is too heavy to be sheared by the shell, a blade may be positioned against the edge of the shell in order to reinforce it during the shearing operation.

For further objects and advantages and for a better understanding of the invention reference may be made to the following description and to the accompanying drawings forming a part of this application and wherein:

Figs. 1A to 1C illustrate diagrammatically successive steps in the cutting off of the side lead-in wire and Fig. 1C shows a fragment of a lamp embodying our invention.

Fig. 2 is a plan view of a preferred mechanism for carrying out the method of our invention, the mechanism being shown in conjunction with a fragment of the turret of a basing machine;

Fig. 3 is a side elevation view of the mechanism of Fig. 2 seen on the lines 3-3.

The invention will be described with reference to an ordinary screw base such as is widely used for household incandescent lamps. It will be understood however that the invention is equally applicable to different sizes and types of bases; for instance the invention may be used with bayonet type bases where the side lead-in wire is connected to the straight-walled cylindrical shell of the base.

Referring to Fig. 1, the successive steps in the basing of a lamp and the shearing 05 of the side lead-in wire in accordance with our invention have been diagrammatically illustrated. In Fig. 1A, a base 1 has been placed over the neck 2 of an electric lamp bulb whereof a fragment 3 has been illustrated. The base comprises a threaded metal shell 4, a metal end contact 5, and an insulating body or web 6 holding the metal parts together. The top lead wire 7 of the bulb is threaded through the eyelet hole 8 in the end contact, and the side lead wire 9 is curved around the neck portion 2 of the bulb and the projecting portion 9 is pulled out at right angles to it below the edge of the base shell. The seal shoulder 10 of the bulb is preferably blown or molded to a size substantially the inside diameter of the skirt of the base shell, so that the side lead wire is wedged between the neck and the base shell at 11.

In Fig. 1B, the projecting portion of the side lead-in wire has been gripped between a pair of jaws 12, 13 which pull the wire upward along the side of the base. The wire is thus bent around sharply below the edge of the shell so that it is stretched and weakened at the point 14 due to the reversal of its direction as between its portions inside and outside the shell. By reason of the fact that the wire is wedged between the base shell and the neck of the bulb, very little stress is transmitted past the point 11 and the possibility of rupturing the seal of the inner portion of the lead into the glass of the bulb is obviated. Moreover by reasons of the direction in which the pull is exerted on the wire, the edge of the base shell acts as a knife which effectively shears ofi the wire without requiring the application of excessive force upon it. The final step in the shearing operation is illustrated in Fig. 1C wherein the lead wire is broken off at the point 14 and the portion 9' is carried away by the jaws.

As illustrated in Fig. 1C, our invention provides an electric lamp of pleasing appearance and wherein the side lead-in wire is sheared 011 at the very edge of the base shell. Thus no part of the side lead-in wire is observable upon casual inspection of the lamp, and the connection of. that wire to the shell of the base is entirely internal 3 and results from the fact that the wire is wedged between the seal shoulder of the bulb and the skirt of the base shell. The need for rolling back the projecting portion of the lead wire against the edge of the shell or for brushing it into the crack between the edge of the base and the neck of the bulb is completely eliminated.

Our invention may conveniently be practiced in conjunction with a prior art lamp finishing machine such as is disclosed for instance in U. S. Patent 1,708,756 Pagan. Referring to Figs. 2 and 3, such a machine may comprise a reel or turret, whereof a fragment is shown at 16, and suitable driving means (not shown in the drawing) for intermittently rotating the turret in a counterclockwise direction as indicated by the curved arrow 17. The intermittent rotation of the turret advances a bulb to a successive work station for each indexing operation. Lamp holders 18 are fastened to the turret around its periphery. Each holder comprises a resiliently mounted bulb cup 19 for engaging the lower end of the bulb, an upper plate 20 having a cavity 21 for receiving the end contact of the base, and a pair of spring biased holding jaws 22, 23 which engage opposite sides of the base. The lamp is held firmly and the base is pressed against the bulb neck by reason of the upward pressure exerted on the bulb by the spring 24 through the bulb cup 19. The pressure exerted on the base by the jaws 22, 23 insures that it is squarely seated on the neck of the bulb.

The bulb 3 with its base I mounted thereon is inserted into a holder of the turret at a loading station by the operator. By reason of the pressure exerted by the cup 19 on the bottom of the bulb, the bulb and the base are pressed together and the side lead-in wire is wedged between the base shell and the seal shoulder of the bulb. The projecting portion 9' of the lead-in wire is gripped between the jaws 12 and 13 which are pivoted at 25 upon a pedestal 26 fastened to frame member 27 of the machine. The upper jaw 13 is pulled down by a spring 28, the extent of its pivoting being limited by a stop 29 atfixed to the pedestal. The lower jaw 12 is actuated by a connecting rod 30 whereof the lower end is hinged on a rocker arm 31 driven by a cam 32. It will be understood that cam 32 is driven in synchronism with the driving means for the turret so as to actuate the jaws at the required moment during the indexing cycle of the turret.

In operation, the turret indexes the bulb into the station and the projecting portion 9" of the side lead-in wire becomes positioned between the open jaws 12 and 13. With the lamp stationary at, the station, the operation of cam 32 pulls connecting rod 30 down, causing lower jaw 12 to pivot up and contact upper jaw 13, at which moment the projecting portion 9 of the lead is gripped. The jaws are now biased together by the force of spring 28 and move upward as a unit, thereby pulling the projecting portion of the lead against the side of the base shell and causing it to be sheared against the edge of the shell.

In the case of the larger sizes of incandescent lamps, the side lead-in wire, which is generally fuse wire, may be too heavy to allow for shearing against the edge of the base without support. In such case, the edge of the base shell may be reinforced for the shearing operation by positioning a sharp blade next to it in a manner to take up some of the shearing stress. A suitable arrangement is illustrated in Fig. 3, and comprises a spring blade 35, fixed at 36 to a frame member of the machine and having a sharp edge 37 which conforms to the side of the base shell. The blade is pressed forward against the base shell thru the engagement of the secondary blade 38 by pin 39 on lower jaw 12 when that jaw is pivoted up. The edge 37 of blade 35 is thus resiliently pressed against the edge of the shell of the base and stitfens it to permit the shearing of relatively heavy lead-in wire.

While the invention'has been described in connection with an ordinary screw base, it Will be realized that it is equally applicable to other sizes and types of bases. Moreover, the apparatus which has been described illustrates but a preferred means for carrying out the method of our invention. The illustrations have been given by way of example only, and the scope of our invention is to be determined by the following claims.

What we claim as new and desire to secure by Letters Patent of the United States is:

In combination, means for pressing a lamp bulb and its base together at a work station, a pair of jaws positioned at said work station and adapted to grip a protruding portion of a lead wire of said bulb, means for moving said jaws with said lead Wire gripped therebetween in a direction-such as to bend said wire sharply around the edge of said shell in order to shear it thereagainst, and means for reinforcing said edge to facilitate shearing of said wire, the last-named reinforcing means comprising a blade member secured at one end at said work station to extend with its free end located adjacent to the base shell at said station, and means operable upon movement of said jaws to press said blade against said base shell.

References Cited in the file of this patent UNITED STATES PATENTS 

